Use @cmdutils.argument for completions

CONTRIBUTING.asciidoc

@@ -453,6 +453,7 @@ The following arguments are supported for `@cmdutils.argument`:
 - `win_id=True`: Mark the argument as special window ID argument
 - `count=True`: Mark the argument as special count argument
 - `hide=True`: Hide the argument from the documentation
+- `completion`: A `usertypes.Completion` member to use as completion.
 
 The name of an argument will always be the parameter name, with any trailing
 underscores stripped.

qutebrowser/app.py

@@ -722,8 +722,8 @@ class Quitter:
         # segfaults.
         QTimer.singleShot(0, functools.partial(qApp.exit, status))
 
-    @cmdutils.register(instance='quitter', name='wq',
+    @cmdutils.register(instance='quitter', name='wq')
-                       completion=[usertypes.Completion.sessions])
+    @cmdutils.argument('name', completion=usertypes.Completion.sessions)
     def save_and_quit(self, name=sessions.default):
         """Save open pages and quit.
 

qutebrowser/browser/commands.py

@@ -226,8 +226,8 @@ class CommandDispatcher:
             tabbar.setSelectionBehaviorOnRemove(old_selection_behavior)
 
     @cmdutils.register(instance='command-dispatcher', name='open',
-                       maxsplit=0, scope='window',
+                       maxsplit=0, scope='window')
-                       completion=[usertypes.Completion.url])
+    @cmdutils.argument('url', completion=usertypes.Completion.url)
     @cmdutils.argument('count', count=True)
     def openurl(self, url=None, bg=False, tab=False, window=False, count=None):
         """Open a URL in the current/[count]th tab.
@@ -863,8 +863,8 @@ class CommandDispatcher:
                 raise cmdexc.CommandError(e)
             self._open(url, tab, bg, window)
 
-    @cmdutils.register(instance='command-dispatcher', scope='window',
+    @cmdutils.register(instance='command-dispatcher', scope='window')
-                       completion=[usertypes.Completion.tab])
+    @cmdutils.argument('index', completion=usertypes.Completion.tab)
     def buffer(self, index):
         """Select tab by index or url/title best match.
 
@@ -1087,8 +1087,8 @@ class CommandDispatcher:
         quickmark_manager.prompt_save(self._win_id, self._current_url())
 
     @cmdutils.register(instance='command-dispatcher', scope='window',
-                       maxsplit=0,
+                       maxsplit=0)
-                       completion=[usertypes.Completion.quickmark_by_name])
+    @cmdutils.argument('name', completion=usertypes.Completion.quickmark_by_name)
     def quickmark_load(self, name, tab=False, bg=False, window=False):
         """Load a quickmark.
 
@@ -1118,8 +1118,8 @@ class CommandDispatcher:
                          "Bookmarked {}!".format(url.toDisplayString()))
 
     @cmdutils.register(instance='command-dispatcher', scope='window',
-                       maxsplit=0,
+                       maxsplit=0)
-                       completion=[usertypes.Completion.bookmark_by_url])
+    @cmdutils.argument('url', completion=usertypes.Completion.bookmark_by_url)
     def bookmark_load(self, url, tab=False, bg=False, window=False):
         """Load a bookmark.
 
@@ -1303,8 +1303,8 @@ class CommandDispatcher:
             message.info(self._win_id, "Dumped page to {}.".format(dest))
 
     @cmdutils.register(instance='command-dispatcher', name='help',
-                       completion=[usertypes.Completion.helptopic],
                        scope='window')
+    @cmdutils.argument('topic', completion=usertypes.Completion.helptopic)
     def show_help(self, tab=False, bg=False, window=False, topic=None):
         r"""Show help about a command or setting.
 

qutebrowser/browser/urlmarks.py

@@ -204,8 +204,8 @@ class QuickmarkManager(UrlMarkManager):
         else:
             set_mark()
 
-    @cmdutils.register(instance='quickmark-manager', maxsplit=0,
+    @cmdutils.register(instance='quickmark-manager', maxsplit=0)
-                       completion=[usertypes.Completion.quickmark_by_name])
+    @cmdutils.argument('name', completion=usertypes.Completion.quickmark_by_name)
     def quickmark_del(self, name):
         """Delete a quickmark.
 
@@ -284,8 +284,8 @@ class BookmarkManager(UrlMarkManager):
             self.changed.emit()
             self.added.emit(title, urlstr)
 
-    @cmdutils.register(instance='bookmark-manager', maxsplit=0,
+    @cmdutils.register(instance='bookmark-manager', maxsplit=0)
-                       completion=[usertypes.Completion.bookmark_by_url])
+    @cmdutils.argument('url', completion=usertypes.Completion.bookmark_by_url)
     def bookmark_del(self, url):
         """Delete a bookmark.
 

qutebrowser/commands/command.py

@@ -40,7 +40,7 @@ class ArgInfo:
     """Information about an argument."""
 
     def __init__(self, win_id=False, count=False, flag=None, hide=False,
-                 metavar=None):
+                 metavar=None, completion=None):
         if win_id and count:
             raise TypeError("Argument marked as both count/win_id!")
         self.win_id = win_id
@@ -48,18 +48,21 @@ class ArgInfo:
         self.flag = flag
         self.hide = hide
         self.metavar = metavar
+        self.completion = completion
 
     def __eq__(self, other):
         return (self.win_id == other.win_id and
                 self.count == other.count and
                 self.flag == other.flag and
                 self.hide == other.hide and
-                self.metavar == other.metavar)
+                self.metavar == other.metavar and
+                self.completion == other.completion)
 
     def __repr__(self):
         return utils.get_repr(self, win_id=self.win_id, count=self.count,
                               flag=self.flag, hide=self.hide,
-                              metavar=self.metavar, constructor=True)
+                              metavar=self.metavar, completion=self.completion,
+                              constructor=True)
 
 
 class Command:
@@ -90,10 +93,9 @@ class Command:
     """
 
     def __init__(self, *, handler, name, instance=None, maxsplit=None,
-                 hide=False, completion=None, modes=None, not_modes=None,
+                 hide=False, modes=None, not_modes=None, needs_js=False,
-                 needs_js=False, debug=False, ignore_args=False,
+                 debug=False, ignore_args=False, deprecated=False,
-                 deprecated=False, no_cmd_split=False,
+                 no_cmd_split=False, star_args_optional=False, scope='global'):
-                 star_args_optional=False, scope='global'):
         # I really don't know how to solve this in a better way, I tried.
         # pylint: disable=too-many-locals
         if modes is not None and not_modes is not None:
@@ -115,7 +117,6 @@ class Command:
         self.hide = hide
         self.deprecated = deprecated
         self._instance = instance
-        self.completion = completion
         self._modes = modes
         self._not_modes = not_modes
         self._scope = scope
@@ -148,10 +149,11 @@ class Command:
 
         args = self._inspect_func()
 
-        if self.completion is not None and len(self.completion) > len(args):
+        self.completion = []
-            raise ValueError("Got {} completions, but only {} "
+        for arg in args:
-                             "arguments!".format(len(self.completion),
+            arg_completion = self.get_arg_info(arg).completion
-                                                 len(args)))
+            if arg_completion is not None:
+                self.completion.append(arg_completion)
 
     def _check_prerequisites(self, win_id):
         """Check if the command is permitted to run currently.
@@ -264,7 +266,7 @@ class Command:
                 log.commands.vdebug('Adding arg {} of type {} -> {}'.format(
                     param.name, typ, callsig))
                 self.parser.add_argument(*args, **kwargs)
-        return signature.parameters.keys()
+        return signature.parameters.values()
 
     def _param_to_argparse_kwargs(self, param, typ):
         """Get argparse keyword arguments for a parameter.

qutebrowser/config/config.py

@@ -686,9 +686,10 @@ class ConfigManager(QObject):
             raise cmdexc.CommandError("set: {} - {}".format(
                 e.__class__.__name__, e))
 
-    @cmdutils.register(name='set', instance='config',
+    @cmdutils.register(name='set', instance='config')
-                       completion=[Completion.section, Completion.option,
+    @cmdutils.argument('section_', completion=Completion.section)
-                                   Completion.value])
+    @cmdutils.argument('option', completion=Completion.option)
+    @cmdutils.argument('value', completion=Completion.value)
     @cmdutils.argument('win_id', win_id=True)
     def set_command(self, win_id, section_=None, option=None, value=None,
                     temp=False, print_=False):

qutebrowser/misc/sessions.py

@@ -356,8 +356,8 @@ class SessionManager(QObject):
                 sessions.append(base)
         return sessions
 
-    @cmdutils.register(completion=[usertypes.Completion.sessions],
+    @cmdutils.register(instance='session-manager')
-                       instance='session-manager')
+    @cmdutils.argument('name', completion=usertypes.Completion.sessions)
     def session_load(self, name, clear=False, temp=False, force=False):
         """Load a session.
 
@@ -384,10 +384,9 @@ class SessionManager(QObject):
                 for win in old_windows:
                     win.close()
 
-    @cmdutils.register(name=['session-save', 'w'],
+    @cmdutils.register(name=['session-save', 'w'], instance='session-manager')
-                       completion=[usertypes.Completion.sessions],
-                       instance='session-manager')
     @cmdutils.argument('win_id', win_id=True)
+    @cmdutils.argument('name', completion=usertypes.Completion.sessions)
     def session_save(self, win_id, name: str=default, current=False,
                      quiet=False, force=False):
         """Save a session.
@@ -420,8 +419,8 @@ class SessionManager(QObject):
                 message.info(win_id, "Saved session {}.".format(name),
                              immediately=True)
 
-    @cmdutils.register(completion=[usertypes.Completion.sessions],
+    @cmdutils.register(instance='session-manager')
-                       instance='session-manager')
+    @cmdutils.argument('name', completion=usertypes.Completion.sessions)
     def session_delete(self, name, force=False):
         """Delete a session.
 

tests/unit/commands/test_cmdutils.py

@@ -174,13 +174,6 @@ class TestRegister:
             pass
         assert cmdutils.cmd_dict['fun'].hide
 
-    def test_wrong_completion_count(self):
-        with pytest.raises(ValueError):
-            @cmdutils.register(completion=['one', 'two'])
-            def fun(arg):
-                """Blah."""
-                pass
-
     def test_star_args(self):
         """Check handling of *args."""
         @cmdutils.register()